Russia was never going to retreat or accept defeat. They view Ukraine in NATO as an existential threat. They will win or the entire country will be destroyed. And before they are destroyed, they will launch nukes.

Russia has escalation dominance. From day one, they have always been willing to take this places we aren’t and can’t. This was simply some hair brained scheme to try and get Russians to suffer and remove Putin. Well, they aren’t suffering economically and Putin is more popular than ever. So, it ain’t happening.